Since it is expected that the use of a point-to-multipoint service (i.e., multicast broadcast service, MBS) that provides the same information to a plurality of users through one link is increased in a wireless network, a method for efficiently supporting the MBS is required. Particularly, the plurality of users receiving the information must have the same complementary relationship with the same connection parameters. In a wideband wireless access communication system, a plurality of portable subscriber stations (PSSs) included in a cell share a connection ID (CID) that is an identifier of a packet transmitted through a radio link so that the plurality of PSSs can receive the same information from one radio access system (RAS).
The MBS is established only through a downlink, and can be divided into a single access method and a multiple access method. The single access method is a method for transmitting a packet from a single RAS to a PSS, and the multiple access method is a method for simultaneously transmitting the same packets from a plurality of RASs to the PSS. According to the multiple access method, the PSS receives the same packets from the plurality of RASs, and therefore the PSS can receive an accurate packet by merging the received packets. In this case, in order to transmit the same packets, the plurality of RASs must insert packets of the same size in the same location in a downlink frame and apply the same coding method, and synchronization between the plurality of RASs is required. However, a method for efficiently supporting the above requirements has not been proposed.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.